Use of apparatus to provide multiple images on photosensitive paper is widespread in the photoprinting art. For example, a photofinisher may employ two or more photographic negatives in a multiple projection system to superimpose images of two or more persons or objects at the same location on the photosensitive paper. The resulting "double-exposure" is designed to enhance the artistic and esthetic qualities of the individual negatives. Similarly, multiple projector systems are utilized in the microfiche industry to record multiple independent images of alphanumatic data onto microfilm, as illustrated in U.S. Pat. No. 4,185,913 issued to Ammann, et al. Other types of multiple imaging systems combine image projection techniques with contact printing techniques to obtain side-by-side exposures of projected pictorial images and contact-printed graphic displays or written messages on photosensitive paper. U.S. Pat. No. 3,424,527 issued to Bremson, Jr., discloses such a combination of image projection/contact printing systems capable of producing advertising or instructional materials or the like. The recently popularized photographic greeting cards also incorporate images generated by contact printing with images generated by projection. A typical photographic greeting card consists of a "family" portrait positioned on one portion of the card and an appropriate greeting or "sentiment" positioned on another portion of the card in spaced relationship to the "family" portrait. During photoprocessing of the greeting cards, a photosensitive strip moving through the photoprocessing machine is exposed to the family portrait using a conventional projection system to project the primary or portrait image from a portrait negative onto the photosensitive strip. The secondary image of the sentiment is reproduced on the photosensitive strip using a contact printer mechanism which applies the sentiment negative directly to the strip surface. This procedure is performed continuously along the entire length of the photosensitive strip and the strip is subsequently developed to yield a plurality of greeting cards which may be separated from one another and returned to individual customers.
With the advent of high-speed computerized photoprinters such as the Kodak 2610 photoprinter, photoprocessing capacities have increased dramatically. Up to one thousand photographic prints can now be exposed per hour. Attempts to coordinate the operation of high-speed photoprinters and prior art contact printing mechanisms during composition of multiple image photographic greeting cards, however, has met with limited success. As can be appreciated, the mechanical lag associated with prior art contact printers seriously restricts the number of multiple images which can be formed on a photosensitive strip in a given amount of time. The processing rate of high-speed photoprinters employed in conjunction with contact printers must therefore be slowed considerably if the contact printing operation is to keep pace with the projection printing operation in the high-speed photoprinter, and much of the high-speed photoprinter capacity is wasted. Under these circumstances, it would be of obvious benefit to provide an apparatus which could be added to existing high-speed photoprinters to provide a high-speed secondary image projection capability which matches the inherent high-speed primary image projection capability of the photoprinter.